A filter designed to remove carbon and other waste byproducts from a combustion process including soot, ash and other debris is herein defined as a “carbon filter.” Carbon filters of this type are typically made from a high temperature material such as cordierite or silicon carbide. Soot and other byproducts of a combustion process are trapped in the carbon filter instead of being released into an operating environment. A carbon filter includes a diesel particulate filter (DPF) or catalyzed diesel particulate filter (CDPF). As defined in this application, a DPF may or may not include a catalyst. In North America, Europe, and other parts of the world, changing emission standards have resulted in many combustion sources, particularly diesel engines, being fitted with DPFs. The DPF traps soot, ash, and other pollutants from the exhaust of the diesel engine. Catalysts in a DPF may help to reduce soot and pollutants in a DPF. Engine exhaust typically does not heat a DPF sufficiently for soot to burn inside the DPF. A catalyst may help to reduce the soot ignition temperature, allowing a “passive regeneration” process within the normal operating duty cycle of an equipped vehicle (i.e. without removing the DPF from the vehicle). However, there continues to be issues with the passive regeneration approach, including incomplete burning of soot and inability to remove ash.
Soot, ash and other debris continuously accumulate over time inside a DPF. This can have the negative consequences of increased pressure drop across the DPF and reduced efficiency of the catalyst. This can further result in increased backpressure upstream of the filter in the engine, and possibly DPF failure. Ultimately, increased backpressure may cause engine failure.